Tool retainer for percussive tools



Nov. 3, 1959 A. J. KEIR ETAL TOOL RETAINER FOR PERCUSSIVE TOOLS Filed July 12, 1957 FIG.3

FIG/ A MAURICE s. HARVEY ALEXANDER J. KEIR INVENTORS BY M United States Patent 1 2,911,224 TOOL RETAINER FOR PERCUSSIVE TOOLS Alexander J. Keir, Springfield, and Maurice S. Harvey,

Willimansett, Mass., assignors to Worthington Corporation, Harrison, N .J a corporation of Delaware Application July 12, 1957, Serial No. 671,544

14 Claims. (Cl; 279-19.5)

The present invention relates to percussive machines and more particularly to tool retainer assemblies foresaid machines, and is a continuation in part of copending application, Serial Number 641,503 filed February 21, 1957, now abandoned.

Tool retainer assemblies have been developed, heretofore, for use in percussive machines when it has been necessary to prevent tool fallout during the operation thereof.

Such tool retainer assemblies generally comprise a latch attached to the machine housing by pivotal means and include a cooperating holding means having a spring pressed pawl, to hold the latch in the engaged or disengaged position. The latch permitting replacement of the tool when disengaged and preventing ejection thereof when engaged.

. One of the major problems coincident with the operation of percussive machines is transmission of the jarring blows, imparted to the tool for operation, to the holding means in the form of severe vibrations which tend to dislodge the spring pressed pawl from engagement with the retainer latch and thereby permit tool fall-out.

Accordingly, it is an object of the present invention to provide the latch of a tool retainer assembly with a positive locking means to hold said latch in operative engagement with a breaker tool, so that disengagement of the latch, due to vibrations resulting from machine operation, will be substantially eliminated.

It is another object of this invention to provide a percussive machine with a retainer assembly including pivotable means for interconnecting said assembly to the housing of said percussive 'machine that is durable, efficient and easily assembled.

With these and other objects in view, as may appear from the accompanying specification, the invention consists of various features of construction and combination of parts which will be first described in connection with the accompanying drawing, showing a tool retainer assembly for percussive machines of a preferred form embodying the invention.

In the drawings:

Figure 1 is a longitudinal section showing the tool re' tainer assembly in operative position.

Figure 2 is a top view of the tool retainer assembly.

Figure 3 is an end view showing the tool retainer assembly in operative position.

Figure 4 is a fragmentary view showing a modified form of pivotable means for interconnecting the latch to the body of the percussive machine.

Figure 5 is a section showing the pivotal means taken on line 5-5 of Figure 4.

Referring more particularly to the drawings, a percussive machine is shown in part and includes a housing 1 having a sleeve 2 therein adapted to receive a breaker tool 3. The tool 3 is provided with collar 4 integral therewith so that sleeve 2 will engage said collar to limit penetration of the tool 3 therein.

Formed integral with the housing 1 is a boss 5 adapted to accommodate a tool retainer assembly generally designated 6 which includes a latch 7 and holding means 8 to be hereinafter described.

The upper portion of the boss 5 for receiving holding means 8 comprises, a longitudinal bore 9, preferably declim'ng towards the axis of the percussive tool 3, and a bore transverse to the axis of said longitudinal bore 9 and communicating with the bottom portion thereof.

i and in point contact relationship with spherical man-'- Parallel legs 11 and 12 extend downwardly from the open end 13 of longitudinal bore 9 in the upper portion of boss 5 and include a coaxial bore 14 therethrough at the end remote from the bore 10 for pivotally connecting the latch 7 therebetween.

The latch 7 consists of a body member 15 including a lever 16 and a stop-face 17; the body member being provided with a bore-18 therethrough for pivotal connection between the parallel legs 11 and 12.

The latch 7 is pivotally mounted between the legs 11 and 12 by inserting a pin means 19, as for example a roll pin as is clearly shown in Figure 1 of the drawings, through the coaxial bore 14 and the bore 18 in the' body member 15.

The stop-face 17 being positioned in engaging relationship with the collar 4 to prevent ejection of the tool during operation of the percussive machine, as is clearly shown in Figure 1 of the drawings.

The roll pin 19 is in press fit relationship with the coaxial bore 14 through the legs 11 and 12 and in loose fit relationship with the bore 18 of the latch'7. The press-fit relationship tends to withstand the dislodging effect of the severe vibrations of the percussive machine; the loose-fit relationship permits pivotal movement of the latch 7 about the roll pin 19.

A roll pin of any well known or approved construction may be used and is purchaseable in the open market. 3

The lever 16 integral with the body member 15 of latch 7 abuts the boss 5 when the stop-face 17 is in engaging position so that further pivotal movement towards the tool axis, tending to disengage the stop-face 17, is eliminated.

Pivotal movement of the stop-face 17 away from the tool axis is resisted by holding means 8 slidably disposed in the upper portion of boss 5 and abutting latch 7 as is clearly shown in the drawing.

The holding means 8 comprises a member 20, a spring 21 and a pawl 22 disposed in the longitudinal bore 9; and a roll pin 23 press fit into bore 10 in point contact relationship with member 20 and co-acting therewith to urge the spring 21 and pawl 22 outwardly into abutment With the latch 7.

Preferably, the member 20 consists of a spherical metal ball, as for example the spherical member commonly used in the manufacture of ball bearings, however it will be evident to those skilled in the art that the concept of the invention will be served by the use of a cylindrical member in place of the spherical member 20, the'concept being the association of roll pin 23 with a curved or spherical surface, which surface permits the insertion of pin 23 in operable position.

The spring 21 is well known and widely used in the art.

The pawl 22, as for example, comprises a cylindrical member having a hollow end for receiving spring 21 and an engaging end 24 having an axial bore 25 therethrough.

The axial bore 25 provides escape means for air that may be entrapped in longitudinal bore 9, which air may interfere with operativcness of holding means 8.

In assembly, the spherical member 20, spring 21 and pawl 22 are slidably disposed in the longitudinal bore 9. The latch 7 is then inserted between the legs 11 and 12 with the stopface 17 in engaging relationship with the collar 4 of the tool 3. The latch being pivotally con- 7 nected therebetween by roll pin 19 in press fit with co- I i axial bore 14 and in loose fit with bore 18.

noted that initial compression is applied tothe spring 21 at this stage of the assembly.

Positive locking and final assembly is obtained by inserting roll pin 23 in press fit-engagement with bore '10 It will be her 20 as is clearly shown in Figure 1 of the drawings to thereby compress the spring 21 to the proper tension in order to resist the latch dislodging efiect resulting from the vibrations of the percussive machine during operation.

It is readily comprehensible that insertion of roll pin 23 into operative position results from the conjunctive use of either a spherical member or a cylindrical member; the greater compression of the spring being a consequence of the sharp rise on the curved surface of said member.

In operation, the pawl 22 is urged outwardly, by the cooperative action of roll pin 23, spherical member 20 and spring 21, into abutment with latch 7 to retain stopface 17 in engaging relationship with collar 4 of tool 3 to prevent ejection thereof during the operation of the percussive machine.

The tool 3 is easily replaced or removed from the housing 1 by applying leverage to the lever 16 which forces the pawl 22 upwardly into the longitudinal bore 9 and permits pivotal movement of the stop-face 17 to a position shown by the dotted lines in Figure l of the drawings.

It has been explained hereinbefore that the latch 7 is 'pivotably interconnected to the legs 11 and 12 by a pin member 19.

Figure 4 shows a modified form of pin member 19' held in operable position in bore 18' by pin means 50 and 51' disposed respectively through bores 54' and 55 in the legs 11 and 12 in abutting relationship with the pin member 19.

The pin member 19' is provided with grooves 52' and 53' for receiving pin means 50 and 51.

The pin means 50' and 51 are roll pins of any well known construction and readily purchasable in the open market.

Assembly of the latch utilizing the modified pivotal means is accomplished as hereinbefore described, the pin member being inserted in coaxial bore 14 and bore 18 and held in operable position by roll pins 50 and 51 inserted through bores 54' and 55' in abutment with the grooves 52' and 53.

It will be understood that the invention is not to be limited to the specific construction or arrangement of parts shown, but that these may be widely modified within the invention defined by the claims.

What is claimed is:

1. In a percussive tool having a tool receiving opening, a latch for said percussive tool to detachably engage a tool disposed in said tool receiving opening, pin means pivotably inter-connecting said latch to said percussive tool, and retainer means in said tool and operatively abutting said latch for retaining said latch in engaged and disengaged position, said retainer means including a spring pressed pawl disposed to engage said latch, a member in abutment with the spring to compress the spring to increase the abutting force of the spring pressed pawl abutting the latch, and a second member in abutment with the first member to further compress the spring to further increase the abutting force of the spring pressed pawl.

'2. In the combination claimed in claim 1 wherein said pawl comprises, a cylindrical body having a hollow end for receiving said spring and a bore axially through said body.

3. In the combination claimed in claim 1 wherein said first mentioned member is spherically formed.

4. In the combination claimed in claim 1 wherein said second member is a roll pin, and said roll pin is disposed transverse to the axis of said spring-pressed pawl.

5. In the combination claimed in claim 1 wherein said pin means is a roll pin.

6. In the combination claimed in claim 1, wherein said pin means is held in operable position by second pin means in abutment therewith.

7. In the combination claimed in claim 4 wherein the pin means is provided with grooved end portions and the second pin means is disposed in the latch in abutment with said grooves to hold said first pin means in operable position.

8. In a percussive tool having a tool receiving opening, a latch for said percussive tool to detachably engage a tool disposed in said tool receiving opening, pin means having grooved end portions pivotably interconnecting said latch to said percussive tool, roll pins in said latch and in abutment with said grooves for retaining said pin means in operable position, and retainer means in said tool and operatively abutting said latch for retaining said latch in engaged and disengaged position, said retainer means including a spring pressed pawl disposed in said tool to engage said latch, a member in abutment with the spring to compress the spring to increase the abutting force of the spring pressed pawl abutting the latch, and a second member in abutment with the first member to further compress the spring to further increase the abutting force of the spring pressed pawl.

9. In a percussive tool having a tool receiving opening, a latch for said percussive tool to detachably engage a tool disposed in said tool receiving opening, pin means having grooved end portions pivotably interconnecting said latch to said percussive tool, roll pins in said latch and in abutment with said grooves for retaining said pin means in operable position, and retainer means in said tool and operatively abutting said latch for retaining said latch in engaged and disengaged position, said retainer means including a spring pressed pawl disposed in said tool to engage said latch, a spherical member in abutment with said spring to compress the spring to increase the abutting force of the spring pressed pawl abutting the latch, and a roll pin in the tool and in point contact with the spherical member to further compress the spring to further increase the abutting force of the spring pressed pawl.

10. A tool retainer assembly comprising a latch, and retainer means operatively abutting said latch for retaining said latch in engaged and disengaged position, said retainer means including a spring pressed pawl disposed to engage said latch, a member in abutment with the spring to compress the spring to increase the abutting force of the spring pressed pawl abutting the latch, and a second member in abutment with the first member to further compress the spring to further increase the abutting force of the spring pressed pawl.

11. In the combination claimed in claim 6 said pawl comprising, a cylindrical body having a hollow end for receiving said spring and a bore axially through said body.

12. In the combination claimed in claim 6 wherein said first mentioned member is spherically formed.

13. In the combination claimed in claim 6 wherein said second member is a roll pin disposed transverse to the axis of said spring-pressed pawl.

14. A tool retainer assembly comprising a latch, and holding means operatively abutting said latch for retaining said latch in engaged and disengaged position, said holding means including, a spring pressed pawl disposed to engage said latch, a spherical member in abutment with said spring to compress the spring to increase the abutting force of the spring pressed pawl abutting the latch and a roll pin in the tool and in point contact with the spherical member to further compress the spring to further increase the abutting force of the spring pressed pawl.

References ited in the file of this patent UNITED STATES PATENTS 2,026,703 Peters Jan. 7, 1936 2,136,190 Gulfelt Nov. 8, 1938 2,400,206 OFarre'll May 14, 1946 2,752,889 Leavell July 3, 1956 

